Schaeffer followed and looked down in disbelief. A riot of water roiled where he'd spent a lifetime of lazy fishing.

"I've never seen anything like it," he said. "Nothing even close."

Eight years out of a decade, 1,440-foot-wide floodgates spill not so much as a bucket of the brown water into the Missouri River.

Now, with the Missouri flooding at record levels over the past two months, enough is barreling out of Lewis and Clark Lake to cover a football field three-and-a-half feet deep every second. Water will race through the dam at that record rate, ultimately swamping farms and towns for hundreds of miles downstream, through August.

"When your bathtub is full, you just can't put any more water in it," said Dave Becker, the operations manager for the U.S. Army Corps of Engineers at Gavins Point. "Water is going to spill over."

But how did the bathtub get so full? Why did the six huge Missouri River reservoirs — including Gavins Point, the farthest downstream — fill to the brim and force the months-long release of floodwater?

The short answer: The Corps could have prevented or drastically held down flooding by opening floodgates sooner. The reasons it didn't — reasons putting government water managers on the spot this summer — rest in a tangle of history, physics, meteorology and politics.

We had ample warning last winter that snow was piling on the Rockies. The Corps made room in its man-made lakes for the coming runoff. Just not enough.

Its engineers point out that the Corps was unaware of the torrents of rain that would deluge the Missouri basin in May. As the river now rises in downtown Kansas City, Mo., and floods soybean fields and hamlets to the north, the Corps insists it couldn't have predicted those storms.

The agency also says it was simply following orders — from us. Over lifetimes and through our politicians, we've said we don't just want those dams to protect us against cataclysm.

We want cheap electricity, and the system gives us plenty of hydropower.

The sparsely populated Dakotas want to keep the reservoirs close to full to draw boaters and sports fishermen, and to irrigate the lower reaches of their river valleys.

Downstream, farming interests want enough water to keep the Missouri River barge industry — a steadily shrinking business — alive.

All that means storing water in the reservoirs in the spring, not leaving empty space to protect against flooding.

"There's a natural tension there," said Brig. Gen. John McMahon, who commands the Corps division that manages the Missouri. "You can't say I'm only for navigation, I'm not for flood control or recreation or whatever....

"They're wicked problems."

In its December 2010 plan, the Corps set aside 22 percent of the capacity of the reservoirs to collect snowmelt and normal spring rains. A century-plus of weather data suggested that would provide enough room for the coming moisture even after a bad winter.

Creating more empty space in the reservoirs certainly was possible, but the competing needs for water — for navigation, power, recreation and other uses required by a mountain of regulations directed by Congress and the courts — explain why the Corps couldn't.

On March 2, with the previous month's snow in the Rockies having been estimated at as much as 50 percent above normal, the Missouri River Basin Forecast Center warned of "major (spring) flooding at many locations" from saturated soil, rain, and "significant snowpack" in the areas above the river.

Then came the unprecedented surprise: Torrential rains began falling in Montana and the upper Midwest, and in mid-May rainfall exceeded anything the Corps had seen in the last century.

The Corps appears to distrust long-range precipitation forecasts, placing much more confidence in history. Its river flood plan relies in large measure on an 1881 Missouri River flood, and each year includes five runoff and release models based on weather statistics back to the 19th century.

"The Corps...isn't very dynamic," said Diane Oerly, president of a Missouri-based group called Friends of Big Muddy. "And they're trying to deal with a dynamic being — the river. If all you do is look to the past to define reality, you can't be too accurate."

Kansas Gov. Sam Brownback has called for a federal investigation of the Corps' decisions. Missouri state Sen. Brad Lager, a Republican who represents hundreds of flooded-out constituents, said the Corps' decisions border on the criminal because it failed to respond adequately to growing snowpack.

"Someone who does this for a living knew this was going to be a problem," Lager said.

McMahon said the criticism was misplaced.

"Nobody likes to have their livelihoods taken away," he said. "We had a whole bunch of unprecedented rain in the upper basin, and that rain fundamentally took away the flexibility that we had built into the system."

Still, there would have been virtually no flooding in 2011 had the Corps let loose far more water earlier. But to do so would have invited criticism from the commercial users of the river worried about drier times later in the year.

"The Missouri River is not a reflection of democratic values. It does not provide equal benefits to all valley residents," said Robert Schneiders, author of "Unruly River." "Instead, the bulk of its benefits go to a few individuals and interest groups in Missouri."

American Rivers, an environmental group that's long been critical of the Corps' management of the Missouri, concedes that it would be impractical to remove the dams — too much commerce depends on having a mostly tamed river.

But perhaps, the organization suggests, it's time to move levees farther back in less populated areas. Move homes out of the flood plain. Give the Missouri more elbow room.

"That way you get more natural storage below the dams," said Shana Udvardy, who studies flood management policy for the group.

In 2009 Congress authorized a five-year study of the current uses for the river, a $25 million effort that's under way but not fully funded. Downstream politicians have fought the study, attributing nefarious motives to its supporters.

David Pope, the executive director of the Missouri River Association of States and Tribes, said that after this year the Corps could gain flexibility to make flood protection a greater priority.

But doing so would risk the outrage of barge operators or municipal water systems left high and too dry at the end of a summer, Pope said. Had this year's rains not been so heavy and had the Corps had let out more water, upstream states likely would have sued for the damage done to their fishing guides and roadside motels.

"You just make a bigger flood pool and have less water in the storage for all the other uses," Pope said. "There is a direct conflict between flood control and navigation. Those are really direct tradeoffs, and you can't have it both ways."

For its part, the Corps promises to take another hard look at its prediction models.

"Now we have a new data point," McMahon said. "Now...we go back and ask if the flood control space is adequate. Should it be more? And if it should be more, at what cost to those other uses?"